3GPP specifies services to allow distributing multimedia content over mobile networks. The document TS 26.243 defines the PSS (for Packet Switched Streaming) service. This service consists in streaming continuous media such as audio and video using RTP (for Real-time Transport Protocol) over UDP (for User Datagram Protocol) as the transport layer. This transport protocol is not reliable: it does not guarantee that the client will get all the data sent by the server. Therefore the content presented to the end-user may be corrupted and it is important for the service provider to monitor the degree of corruption in order to implement a customer-care policy or to adapt its billing strategy.
In 3GPP PSS Release 6, some metrics are defined in order to report to the service provider the quality of experience (QoE) of the end-user. One of this metric is the corruption duration of a media. For non-predictive coding format, the measure is straightforward since a packet loss exactly results in the corruption of one media access unit (i.e. one elementary element of the media). On the contrary, for predictive coding scheme there is no direct mapping between a packet loss and the corruption effect. Errors propagate across the decoded sequence and it is not easy to know accurately when the decoded media is no longer corrupted. This is particularly true for conventional video coding scheme (MPEG, H263, H264).